31325 research outputs found
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Remote sensing-derived time series of transient glacier snowline altitudes for High Mountain Asia, 1985–2021
No full textThe article processing charge was funded by the Open Access Publication Fund of Humboldt-Universität zu Berlin.This study presents a new dataset of remote sensing-derived Transient Snowline Altitude (TSLA) measurements for glaciers in High Mountain Asia. We use the Google Earth Engine to obtain TSLA data for approx. 2.8 · 10 4 glaciers larger than 0.5 km 2 . After filtering and postprocessing, the dataset comprises ca. 9.66 million TSLA measurements with an average of 341 ± 160 measurements per glacier, covering the time span 1985 to 2021.Deutsche Forschungsgemeinschaft (German Research Foundation)https://doi.org/10.13039/501100001659Inge Grünberg’s contribution was financially supported by Geo.X, the Research Network for Geosciences in Berlin and Potsdam.Peer Reviewe
Optimisation of postharvest treatments for food safety and nutrition-sensitive quality assurance of African indigenous vegetables
No full textAfrikanisches einheimisches Gemüse (AIVs) ist sehr verderblich mit hohen quantitativen und qualitativen Nachernteverluste, beschleunigt durch mikrobiellen Verderb und unsachgemäße Nacherntebehandlung. Dieser Dissertation untersuchte mikrobielle Aspekte der Lebensmittelsicherheit entlang der Lieferkette frischem Amaranth. Vorbehandlung und Trocknung mittels Osmodehydratation nach der Ernte, Verpackung in biologisch abbaubarer Folie und Verdunstungskühlung wurden evaluiert. Umfassende Bewertung mikrobieller Aspekte der Lebensmittelsicherheit entlang der 5 wichtigsten Knotenpunkte der Lieferkette bewiesen das Vorhandensein von Indikatormikroorganismen und Virulenzgenen. Die Prävalenz und Kontaminationsgrade nahmen von Bauernhöfen bis Supermärkte zu, mit Einzelhandelsmärkte als kritischsten Kontaminationsorte, wobei an allen Orten festgestellten Kontaminationswerte die empfohlenen Grenzwerte überschritten. Notwendige Voraussetzungen für besseren Erhalt ernährungsphysiologischer und gesundheitsfördernden Eigenschaften getrocknetem Amaranth durch osmotische dehydratation (OD) als Vorbehandlung vor der Ofen- und Gefriertrocknung wurden geschaffen. Anwendung der OD mittels osmotischer Lösung (NaCl) in einer Konzentration zwischen 2,5 & 10 %, Temperatur von 20 - 40 °C und 60 Minuten Eintauchzeit lieferte beste Ergebnisse zur Sicherung ernährungsphysiologischer Qualität. Folienverpackungen erwiesen hilfreich für die Kühllagerung, sie verlängerten die Haltbarkeit und verbesserten Qualitätsmerkmalen wie Erhaltung der grünen Blattfarbe, Reduzierung Frischgewichtsverlusten, Erhalt von Nährstoffen und gesundheitsfördernden Inhaltsstoffen. Netzunabhängige Kühllagerstrukturen mit Verdunstungskohle und Ziegeln für Amaranth und Afrikanischem Nachtschattengewächs Nacherntelagerung bewiesen sich praktikabel und effektiv. Dokumentierten Sicherheitsaspekte, OD sachgemäße Anwendung, biologisch abbaubare Folienverpackungen und Verdunstungskühllager können Nachernteverluste minimieren.African indigenous vegetables (AIVs) are highly perishable and therefore experience high quantitative and qualitative postharvest losses, accelerated by microbial spoilage and inappropriate postharvest handling. In this thesis, microbial food safety aspects were assessed along the supply chain of fresh amaranth. Subsequently, postharvest osmodehydration pre-treatment & drying, biodegradable film packaging, and evaporative cold storage were evaluated. Assessment of microbial aspects of food safety along the main nodes of the fresh amaranth supply chain revealed the presence of indicator microorganisms and virulence genes. Their prevalence and contamination levels increased from farms to supermarkets. Retail markets were the most critical point of contamination, although contamination levels detected at all points exceeded recommended thresholds. Further, conditions necessary to ensure better retention of nutritional and health-promoting properties of dried amaranth through application of osmotic dehydration (OD) as a pre-retreatment before oven and freeze drying were documented. Applying OD at osmotic solution (NaCl) concentration between 2.5-10%, temperature of 20-40°C, and immersion time of 60 minutes provided the best results for nutrition-sensitive quality assurance of amaranth. In chapter 5, the key insight was that film packaging can complement the need for cold storage of amaranth as it extended shelf life and contributed to better quality attributes such as green leaf colour retention and fresh weight loss reduction, as well as preservation of nutritional and health-promoting compounds. Additionally, it was demonstrated that the off-grid, evaporative charcoal and brick cold storage structures are feasible and effective for postharvest storage of amaranth and African nightshade. The safety aspects documented, inappropriate application of OD, biodegradable film packaging, and evaporative cold storage can contribute to minimising postharvest losses
Mitigating triplet loss in 2D WSe2/non-fullerene heterostructures using halogenated acceptors†
No full textTwo-dimensional transition metal dichalcogenides (2D TMDCs) can be combined with organic semiconductors to form hybrid van der Waals heterostructures. Specially, non-fullerene acceptors (NFAs) stand out due to their excellent absorption and exciton diffusion properties. Here, we couple monolayer tungsten diselenide (ML-WSe2) with two well performing NFAs, ITIC, and IT-4F (fluorinated ITIC) to achieve hybrid architectures. Using steady state and time resolved spectroscopic techniques, we reveal sub-picosecond free charge generation in the heterostructure of ML-WSe2 with ITIC, where however, bimolecular recombination of spin uncorrelated charge carriers with possible contributions from geminate charge recombination cause rapid formation of low-lying triplet (T1) states in ITIC. Importantly, this unwanted process is effectively suppressed when the fluorinated derivative of ITIC, IT-4F, is deposited on ML-WSe2. We observe a similar scenario when replacing the ML-TMDC with copper thiocyanate (CuSCN) as the hole acceptor meaning that triplet state formation is not driven by the spin–orbit coupling of ML-WSe2. From ab initio calculations based on density functional theory, we interpret the high triplet formation in the ML-WSe2/ITIC hybrid bilayer due to changes in the nature and energies of the interfacial charge transfer (CT) levels. Our results highlight the delicate balance between excitons and charges in such inorganic/NFA heterostructures.Peer Reviewe
Using net-zero carbon debt to track climate overshoot responsibility
No full textCurrent emissions trends will likely deplete a 1.5 °C consistent carbon budget around the year 2030, resulting in at least a temporary exceedance, or overshoot. To clarify responsibilities for this budget exceedance, we consider “net-zero carbon debt,” a forward-looking measure of the extent to which a party is expected to breach its “fair share” of the remaining budget by the time it achieves net-zero carbon emissions. We apply this measure to all vetted mitigation scenarios assessed in the Intergovernmental Panel on Climate Change’s Sixth Assessment Report and two scenarios that model current policies and pledges, using an illustrative equal per capita allocation of a remaining 1.5 °C carbon budget starting in 1990. The resulting regional carbon debt estimates inform i) the scale and pace of regional carbon drawdown obligations necessary to address budget exceedance and ii) relative regional responsibilities for increased lifetime exposure to extreme heatwaves across age cohorts due to budget exceedance. Our work strengthens intergenerational equity considerations within an international climate equity discourse and informs the implementation of effort-sharing mechanisms that persist beyond the exhaustion of a rapidly dwindling remaining carbon budget
Cultural Influence of Local Food Heritage on Sustainable Development
No full textThis article explores relations between cultural heritage and cultural values for sustainable development in the Enugu region. It discusses the potential to advance a cultural approach to sustainable development of regions by examining the cultural food heritage and relating it to cultural values. Based on empirical research, the article employed a mixed-methods approach to examine the relationship between the identified major local food heritage and cultural values for sustainable regional planning and development. The study examined primary data from 380 community elders, traders, and relevant institutions—including the Ministry of Arts and Culture and the Ministry of Agriculture—through interviews, participant observation, and questionnaires. Data were analyzed using SPSS and Pearson product–moment correlation. Findings identified eight local food heritages and six cultural values. The findings suggest that promoting and preserving local food heritage can be crucial in fostering sustainable cultural values and contributing to sustainable regional development. The local food had a statistically significant influence on cultural values. The Pearson correlation result ( p -value = 0.000) shows a strong correlation between the local food heritage and cultural values for sustainable regional planning and development. However, the study also identified several challenges threatening the sustainability of local food heritage in the region, including high costs, small-scale farming, insecurity, climate change, and poor transportation. The study recommends the development and implementation of comprehensive policies and programs that prioritize the preservation and promotion of local food heritage while addressing the identified challenges.This research received no external funding.Peer Reviewe
When Infrastructure is a Verb
No full textWie infrastrukturiert man? Was bedeutet es, wie fühlt es sich an und was passiert, wenn Infrastruktur ein Verb ist? Die größte Einschränkung bei der Beantwortung dieser Fragen ist eine andauernde Flucht vor der Nominalisierung. Weitere daraus folgende Einschränkungen sind sehr wenige direkte und in-text Zitationen und vier alleinstehende Kapitel – ein Essay als Basis, Zeichnungen als Zwischenspiel, den Löwenanteil in Form eines Romans und Q&A als die Zugabe. Jedoch geht es in dieser Arbeit nicht nur darum sich verschiedenen Textformen zu widmen. Sie erwächst vor allem aus einer empirischen Studie der sanitären Infrastruktur, wobei “sanitär” als ein sozio–technischer Euphemismus für Abwasser, ein vornehmer Begriff, entschuldigen Sie, für Scheiße, steht. Der Ausgangspunkt ist dabei die Stadt Jakarta, wo die meisten Fäkalien der 10.000.000 Menschen unbehandelt bleiben. Durch polymorphes Engagement breite ich mich bis über die Stadtgrenzen aus und komme sprichwörtlich mit den Infrastrukturierenden in Kontakt: Menschen aus der ganzen Welt, die an der Infrastruktur arbeiten, mit ihr verbunden sind und aus der sie besteht. Ich trage zusammen, was sie getan haben, abstrahiere, synthetisiere und biete ein paar nominale Definitionen darüber was Infrastruktur und infrastrukturieren ist und wie man letzteres tut. All das soll ernsthaft als ein Vehikel für das “ethnographic feel” dienen, welches ich hoffe, dass es Sie tief in Ihrem Inneren berühren kann.How to infrastructure? What does it mean, how does it feel, and what happens when infrastructure is a verb? The number-one writing constraint in answering these questions is sustained runaway from Nominalization. It follows that some of the other constraints are near-zero direct quotation and in-text citation, and stand-alone four chapters, that consists of Essay as the foundation, Drawing the interlude, Novel the lion’s share, and Q&As the encore. But it’s not only about writing. It grows from the empirical study of sanitary infrastructure, with "sanitary" as a sociotechnical euphemism for wastewater or sewage, itself a genteel term for, excuse me, poo. The ground zero is Jakarta, where most of the more than 10 million humans' wastes are untreated. By means of polymorphous engagement, I spider beyond the city itself and get in touch by any means with the infrastructurers, people all over the globe who are working on and connected to and constitute the infrastructure, and collate what they have been doing and abstract and synthesize and offer some nominal definitions of what is and what is to and how to infrastructure. Which actually are a vehicle for the ethnographic feel that I wish you can feel in your bones
‘What damage could a small breeze do to a fence?’ The lack of collective action on ride-hailing platforms in Berlin and Tallinn
No full textThe proliferation of ride-hailing platforms in the last decade has been challenged by workers’ mobilization around the world. In order to complement the existing research on successful organizing, in this article the authors investigate the lack of collective resistance in two cases. By comparing the ride-hailing industry in Berlin (Germany) and Tallinn (Estonia), the authors explain the absence of collective mobilization in these different contexts. While ride-hailing in Berlin is more regulated than in Tallinn, drivers in both cities are structurally located in the weakest position within labour relations. Their isolation presents common features found in the business model and the work process, but also within wider societal structures and ideological landscape.horizon 2020 framework programme https://doi.org/10.13039/100010661Peer Reviewe
Forschungsdatenpublikation zur Masterarbeit "Forschungsdatenwebseiten: eine Online-Inhaltsanalyse mit Schwerpunkt auf Metadaten"
No full textDieser Datensatz enthält alle Forschungsdaten, die im Rahmen der Masterarbeit "Forschungsdatenwebseiten: eine Online-Inhaltsanalyse mit Schwerpunkt auf Metadaten" generiert wurden. Es wurde eine Inhaltsanalyse von Webseiten durchgeführt, die Forschungsdaten enthalten, beschreiben oder auf sie verweisen. Die Analyse wurde auf der Grundlage der folgenden vier Hauptkategorien durchgeführt: Art der Webseite, Art der Datensätze, Metadaten und URL-Granularität.
Die Datenerhebung erfolgte im November 2023, die anschließende Analyse und Auswertung fanden von Dezember 2023 bis Februar 2024.This dataset contains all research data generated as part of the master's thesis “Research data webpages: an online content analysis with focus on metadata”. The analysis involved examining web pages that either contain, describe, or refer to research data. The analysis was conducted based on the following four main categories: Webpage type, dataset type, metadata and URL granularity.
The data collection took place in November 2023, the subsequent analysis and evaluation took place from December 2023 to February 2024
Investigation of the photocycle of bacterial phytochromes Agp1 and Agp2 using FTIR spectroscopy
No full textDie Phytochromfamilie umfasst lichtempfindliche Proteine, die wichtige Regulationsprozesse in Pflanzen, Bakterien und Pilzen steuern. Im pflanzenpathogenen Bakterium Agrobacterium fabrum absorbieren die Phytochrome Agp1 und Agp2 mithilfe eines kovalent gebundenen Biliverdin-Chromophors Licht im roten bis nahinfraroten Bereich. Aufgrund dieser Eigenschaften sind sie für optogenetische Anwendungen von großem Interesse. In dieser Arbeit wurden Agp1 und Agp2 mittels FTIR- und UV-Vis-Spektroskopie untersucht. Ein neu entwickelter Messaufbau mit Helium-Kryostat ermöglichte Messungen bis 4 K. Dabei konnte das Meta-F-Intermediat von Agp2 analysiert werden, das einen Verzweigungspunkt zwischen produktivem und unproduktivem Reaktionsweg darstellt. Die Experimente zeigten, dass hohe Lichtintensität und Temperatur die Bildung des aktiven Zustands fördern, was auf eine zusätzliche Funktion als Temperatursensor hindeutet. Für Agp1 wurden erstmals Intermediate bei Tiefentemperatur FTIR-spektroskopisch erfasst. Eine pH-abhängige Untersuchung legt eine Keto/Enol-Tautomerie der C19=O-Gruppe des Ring D nahe. Als Protonendonor wird Histidin 280 vermutet. Kryo-Messungen zeigten in beiden Phytochromen Schwingungsänderungen im Carbonylbereich, was auf frühe photochemische Reaktionen hinweist. Für Agp2 wurden zwei frühe Lumi-F-Photoprodukte (ELF1, ELF2) postuliert. Die Ergebnisse wurden durch Raman-Spektroskopie und QM/MM-Berechnungen ergänzt und in einer gemeinsamen Publikation veröffentlicht. Eine weitere ist in Vorbereitung.The phytochrome family comprises light-sensitive proteins that regulate key processes in plants, bacteria, and fungi. In the plant pathogen Agrobacterium fabrum, the phytochromes Agp1 and Agp2 use a covalently bound biliverdin chromophore to absorb light in the red to near-infrared range, making them highly relevant for optogenetic applications. In this study, Agp1 and Agp2 were investigated using FTIR and UV-Vis spectroscopy. A newly developed setup including a helium cryostat enabled measurements down to 4 K. This allowed detailed analysis of the Meta-F intermediate of Agp2, which represents a branching point between productive and unproductive photoconversion pathways. The results show that higher light intensity and temperature promote formation of the active state, suggesting an additional role as a temperature sensor. For Agp1, low-temperature FTIR spectroscopy enabled the first observation of early intermediates. pH-dependent measurements indicate a keto/enol tautomerization of the C19=O group on ring D. Histidine 280 is proposed as the proton donor involved in this process. Cryogenic spectra revealed vibrational changes in the carbonyl region for both phytochromes, indicating early photochemical events. For Agp2, two early Lumi-F photoproducts (ELF1 and ELF2) are proposed. The findings were complemented by Raman spectroscopy and QM/MM calculations and published as part of a collaborative study. A second publication is currently in preparation
A new phylogenetic framework for the genus Kalanchoe (Crassulaceae) and implications for infrageneric classification
No full textBackground and Aims: Kalanchoe is a diverse genus in the Crassulaceae, with centres of diversity in Madagascar and sub-Saharan Africa. The genus is known for its popularity in horticulture, its use as a model system for research on CAM photosynthesis and vegetative reproduction, its high invasive potential and its use in traditional medicine. The genus-rank circumscription and infrageneric classification of Kalanchoe have been the subject of debate for centuries, especially regarding the status and rank of what is now treated as K. subg. Bryophyllum and K. subg. Kitchingia. We aim to generate a densely sampled phylogeny of Kalanchoe s.l. and evaluate the current infrageneric classification system. Methods: We inferred a phylogenetic tree for Kalanchoe using a ddRAD sequencing approach, covering 70 % of taxa and four out of five subgenera currently recognized in the genus. Key Results: We recovered four well-supported clades, partially corresponding to the current subgeneric classification. Kalanchoe subg. Calophygia resolves as sister to the rest of the genus. The relationships among the three remaining clades, however, receive less support. The predominantly mainland African K. subg. Kalanchoe forms a strongly supported clade that resolves as sister to K. subg. Bryophyllum. These two clades are together sister to a clade containing mainly species from K. subg. Kitchingia and K. sect. Pubescentes. Conclusions: The current subgeneric classification of Kalanchoe is partially backed up by our phylogenetic tree but requires further refinement. The tree topology suggests a Malagasy origin of the genus and one dispersal event to the African mainland, with subsequent dispersal from continental Africa to the Arabian Peninsula and Southeast Asia. The formation of bulbils on the leaf margin is restricted to a larger clade within K. subg. Bryophyllum and thus only evolved once. Our tree provides a framework for further taxonomic, evolutionary and physiological research on the genus.Peer Reviewe